1. Field of the Invention
The present invention relates to a lubrication structure for an internal combustion engine, and more particularly to a lubrication structure permitting optimum arrangement of lubrication system components and size reduction of an internal combustion engine for a vehicle.
2. Background Art
Generally, a lubrication system for an internal combustion engine guides oil from a pump chamber arranged near an inner side of the internal combustion engine to the oil filter arranged near the outer side of the internal combustion engine. An example of a similar arrangement is shown in Japanese Patent Laid-open Publication No. Hei. 9-88538.
FIG. 8 is a cross-sectional view of a section of an internal combustion engine taken in the vicinity of an oil pump shaft as found in the conventional art. A clutch cover 02xe2x80x2 is joined to a right surface of a right crankcase 01xe2x80x2. An oil pump shaft 04xe2x80x2 is pivotally supported between the right crankcase 01xe2x80x2 and the clutch cover 02xe2x80x2 oriented in a lateral direction parallel to a crankshaft 03xe2x80x2.
An oil pump 05xe2x80x2 is provided at an end of this oil pump shaft 04xe2x80x2 at the right crankcase 01xe2x80x2 side, and is connected to an oil filter 06xe2x80x2 provided in a manner projecting from the clutch cover 02xe2x80x2 by an oil passageway 07xe2x80x2.
The main oil passageway 07xe2x80x2 is formed having an oil passageway 7cxe2x80x2 passing an oil passageway way 07bxe2x80x2 curving upwards from an oil passageway 07axe2x80x2 extending to the left from the side surface of the pump chamber of the oil pump at the right crank case 01xe2x80x2 side. The main oil passageway 07xe2x80x2 curves vertically and extends in a lateral direction, the oil passageway 07cxe2x80x2 communicating with an oil passageway 07dxe2x80x2 on the clutch cover 02xe2x80x2 side. At the end of the oil passageway 07dxe2x80x2 one branch passageway 07exe2x80x2 branches upwards to an oil filter 6xe2x80x2, and another branch passageway 07fxe2x80x2 is connected to an oil relief valve arranged between an oil pump shaft 04xe2x80x2 and the oil passageway 07dxe2x80x2. 
Since the oil filter 06xe2x80x2 is provided on the clutch cover 02xe2x80x2 at the outside of the internal combustion engine, the degree of freedom of arrangement of the oil filter 06xe2x80x2 is low, and oil passageways 07axe2x80x2, 07bxe2x80x2, 07cxe2x80x2 guiding oil from the oil pump 05xe2x80x2 provided at the right crank case 01xe2x80x2 inside the internal combustion engine to the oil filter 06xe2x80x2 detour in an open-ended square shape, making the passageway complicated and difficult to manufacture.
As the oil passageways 07axe2x80x2, 07bxe2x80x2, 07cxe2x80x2, 07dxe2x80x2 form an open-ended square while detouring around the oil relief valve 08xe2x80x2, a wide space is required to arrange the oil distribution route. Furthermore, this causes the oil filter 06xe2x80x2 to be arranged in a further extended condition. These conditions make it further difficult to reduce the size of the internal combustion engine.
The present invention overcomes the shortcomings associated with the related art and achieves other advantages not realized by the related art.
An aspect of the present invention is to provide a lubrication structure for an internal combustion engine that permits a reduction in size of the internal combustion engine.
An additional aspect of the present invention is to provide a high degree of freedom with respect to oil filter arrangement that benefits from a simple oil passageway that is easy to process and requires relatively small spaces for arrangement.
These and other aspects of the present invention are accomplished by a lubrication structure for an internal combustion engine comprising an oil pump provided at a first end of an oil pump shaft, the oil pump shaft arranged in parallel with a crankshaft; a plurality of oil passageways extending from a side surface of a pump chamber of the oil pump to a second end of the oil pump shaft, the oil passageways arranged in parallel with the oil pump shaft; an oil filter positioned facing towards the oil passageways; and an oil communicating passageway extending vertically from a first oil passageway to the oil filter.
These and other aspects of the present invention are accomplished by a lubrication structure for an internal combustion engine, the internal combustion engine including a crankcase divided into a left crankcase and a right crankcase along a longitudinal centerline, and having a crankshaft arranged transversely therein, the lubrication structure comprising an oil pump having a pump chamber provided at a first end of an oil pump shaft, the oil pump shaft arranged in parallel with the crankshaft; a plurality of oil passageways extending from a side surface of the pump chamber of the oil pump to a second end of the oil pump shaft, the oil passageways arranged in parallel with the oil pump shaft; an oil filter positioned facing towards the oil passageways; an oil introduction passageway extending vertically from a first oil passageway to the oil filter; and an oil discharge port forming an oil supply passageway from an oil pan positioned in a lower portion of the crankcase.
With this simple oil passageway arrangement having an oil passageway formed from a side surface of the pump chamber of the oil pump to another end of the oil pump shaft parallel to the oil pump shaft, and a communicating passageway extending to the oil filter towards the oil passageway vertically without bypassing the oil passageway, the lubrication system is easy to manufacture, the space for arrangement can be reduced, and the protrusion of the oil filter from the internal combustion engine can be suppressed. Therefore the size of the internal combustion engine can be reduced.
As it is capable of extending the communicating passageway vertically from any position of the oil passageway to connect to the oil filter, the degree of freedom of oil filter arrangement is increased.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.